1. Field of the Invention
The present invention relates to a camera accessory, a camera body and a camera system.
2. Description of Related Art
A camera system known in the related art may include contact points to enable communication between the camera body and an exchangeable lens (photographic lens). In such a camera system, engagement/disengagement of the exchangeable lens may be detected via the communication contact points. For instance, Japanese Laid Open Patent Publication No. H8-95144 discloses a camera system that detects engagement of a photographic lens barrel via a communication line BINTL between the photographic lens barrel and the camera body. Since the communication line BINTL is utilized both for inputting data to the camera body and for outputting data from the camera body, a BCPU inside the camera body needs to switch a terminal of the communication line so as to allow the terminal to function as an input terminal when detecting photographic lens barrel engagement/disengagement and to switch the same terminal so as to allow it to function as an output terminal when conducting communication.